Mimosa setuligera

  • Title

    Mimosa setuligera

  • Authors

    Rupert C. Barneby

  • Scientific Name

    Mimosa setuligera Harms

  • Description

    178. Mimosa setuligera Harms, Bot. Jahrb. Syst. 42: 208. 1908.—"Bahia: Taboleiro bei Remanso (ULE n. 7388—Jan. 1907)."-Holotypus, +B = F Neg. 1437!; isotypi, G! HBG! K! = NY Neg. 11646.

    Functionally herbaceous subshrub with slender, pliantly humifuse, simple or few-branched, distantly foliate stems attaining ± 1 m, these with petioles and peduncles at once viscid-villosulous and hispid with minute pallid simple hairs, erect gland-tipped setulae to ±0.4-0.6 mm, and horizontally spreading yellowish plain setae to 2-3 mm, the small firm concolorous lfts either glabrous or dorsally finely villosulous, the globose capitula long-pedunculate in distal lf-axils, ascending to meridian. Stipules deflexed, lanceolate or ovate, abruptly acuminate ±3-5 x 1.2-2 mm, hirsutulous on both faces, setose-ciliolate, coarsely 1-3-nerved, persistent. Leaf-stalks 3-6 cm subterete, the petiole including livid pulvinus 11-17 mm, at middle 0.4-0.5 mm diam., the interpinnal segments 2-8 mm, thinly setose but otherwise glabrate; no interpinnal spicules; pinnae (6—)8—11-jug., decrescent proximally, the rachis of distal ones 6-11 mm, the interfoliolar segments 0.3-0.7 mm; lfts of longer pinnae 9- 12(-13)-jug., subequilong, closely imbricate, the first pair 1-1.5 mm distant from a pair of setae on top of pulvinus, the blades narrowly oblong-obovate obtuse 2-3 x 0.9-1.2 mm, ±2-3 times as long as wide, veinless on both faces or the midrib weakly discolored dorsally but not raised. Peduncles solitary or geminate ±4-5 cm; capitula without filaments 7-8 mm diam., prior to anthesis moriform; bracts oblanceolate ± 1 mm, dorsally puberulent; flowers 3(-4)-merous diplo-stemonous, some small proximal ones staminate; pedicels ±0.2 mm; calyx campanulate ±0.6 mm, glandular-puberulent externally; bisexual corollas vase-shaped ±2.9-3.5 mm, the faintly 1-nerved lobes 1-1.4 x 1 mm, beyond middle thinly minutely hispidulous and viscid-setulose; filaments (presumably pink) shortly monadelphous around base of pistil, exserted ±5.5 mm; ovary obscurely puberulent. Pods (scarcely known) ±65 x 6 mm, the replum hispid.

    In taboleiro ±300—400 m, known only from lower S. Francisco valley near 9°40'S in n. Bahia (Petrolina; Joàzeiro, Remanso), and from adj. Piauí (Sa. do Cavalheiro).—Fl. I-V.

    This elegant prostrate mimosa is clearly akin to M. brevipinna and M. borboremae, perhaps not specifically distinct from the former, with which it agrees closely in the entire mucronate stipules, in leaf-formula, and in the random tetramerous flowers. The weak differential characters that distinguish M. setuligera from M. brevipinna are found in length and dispersal on the plant of epidermal outgrowths: dense hispid pubescence of the perhaps weaker and longer stems; pinna-rachises glabrous except for a peculiar pair of setae arising from points occupied in most tetramerous Mimosae by the paraphyllidia (modified leaflets); and viscid-hispidulous calyx and corolla-lobes. At present M. brevipinna is known only from the type and M. setuligera only from the type and one modem collection (Heringer & al. 364, NY), so it is too early to assess the significance of the characters, which may prove variable. The disparity in length of peduncle to the associated leaf, thought by Harms to be distinctive, is unlikely to prove a dependable character in the context of this group.